A method and apparatus are described for percutaneous myocardial revascularization of a human heart. A deflectable elongated flexible lasing apparatus is used which includes a source of laser radiation, an elongated flexible radiation conveying means for conducting the laser radiation to a lens on the distal end of the radiation conveying means for focusing the laser radiation, and control lines for deflecting the distal end of the radiation conveying means. The control lines are secured to the distal end of the radiation conveying means for changing the angle of deflection of the distal end of the radiation conveying means. The lasing apparatus is guided to an area within the patient's heart, and the distal end of the lasing apparatus is directed to an area of interest where the inner wall of the heart is irradiated with laser energy to form a channel through the myocardium for a desired distance. In a preferred embodiment, channels are formed without perforating the epicardium of the heart.